That's right, you heard me. Apparently early man was once hunted by vicious birds, according to soon-to-be-replaced research from some research institute or something.
Researchers have long suspected that early man may have been plagued by birds who would swoop down, flap their wings a lot, and then land on early man's shoulder. This vicious behavior was so scary that early man would then respond by dying. Thousands of cavemen were terrorized by vicious birds like this one.
The only protection against birds like these is cowboy hats. Vicious birds of prey are afraid of cowboy hats. Unfortunately, cavemen didn't have cowboy hats, so they would die, only to have their delicious brains eaten by birds like this one.
So let this be a lesson to you. Wear your cowboy hat!